Evaluation of effect of highly standardized aqueous extract of roots and leaves of Withania somnifera on cold pressor test induced cardiovascular changes in healthy human subjects

Abstract

Background: Stress is an important cardiovascular risk factor. Cold pressor test (CPT) is a simple, validated, non-invasive test used to measure stress induced changes in cardiovascular parameters. The objective of this study was to evaluate effect of Withania somnifera extract on cold pressor stress test induced changes on cardiovascular parameters and aortic wave reflections in healthy human subjects. Methods: This was a double-blind, placebo controlled, crossover study. Participants were randomized to receive either two capsules of Withania somnifera extract 250 mg or two capsules of placebo twice daily for 14 days. Pharmacodynamic parameters heart rate, aortic pressure, augmentation index (AIx), subendocardial viability ratio (SEVR), radial and aortic blood pressure (BP) were recorded before and after CPT at baseline and at end of treatment. After washout period of 10 days, subjects crossed over to other treatment group and same procedure was repeated. Safety assessments were done at baseline and at end of treatment. Results: A total of 20 volunteers completed the study. Compared with baseline and placebo, Withania somnifera extract produced a significant decrease in mean percent change of arterial stiffness indices (AIx, radial and aortic BP). SEVR with CPT increased, however it was non-significant compared to baseline and placebo. Both treatments were well-tolerated and no serious adverse events were reported. Conclusions: Withania somnifera extract showed a significant decrease in cold pressor stress test induced changes on aortic wave reflections, suggesting its beneficial effects in reducing stress induced cardiovascular changes. However, further clinical studies are warranted to evaluate these effects in patients with cardiovascular and other associated diseases.